Guys, for aggregation and composition think of it this way Aggregation(empty rectangle): If a dog breed goes extinct, dogs don't go extinct. Composition(filled rectangle): If dogs go extinct, the dog breed also goes extinct.
Reworded in a more lengthy fashion: Aggregation: The 'Dog' contains a multitude (aggregation) of 'Breeds'; therefore, if a 'Breed' disappears, the 'Dog' remains. Composition: Each 'Breed' is made up of (composed of) 'Dog'; therefore, if 'Dogs' disappear, 'Breeds' can no longer exist.
sorry to be so off topic but does anyone know a trick to log back into an Instagram account..? I somehow lost the account password. I appreciate any assistance you can offer me!
Since Dog is a (sub-)class implementing and inheriting methods from the abstract Animal class, the arrow should be on the other side (see video at 14:05)
You're very welcome :) An Association occurs when a class contains a reference to another class "Has a". An Aggregation and a Composition are both Associations, but are more complex Associations. An Aggregation occurs when a class contains another class and the contained class can exist without the container class. A Composition ("Part of") also has a class that contains another. The only difference is that the contained can't exist without the container. I hope that helps
From your explanation of Aggregation & Composition, I think you got the notations wrong. Composition should be the filled diamond while Aggregation is the empty diamond. But you used them in the reverse.
+Derek Banas you should create an annotation to let people know about that mistake. Luckily I saw this comment, but others might not see it. Anyways thanks a lot for this video.
+Derek Banas You made one more error. The arrow should be pointing on to the abstract class Animal and not the subclass as it is presented in the video. The "Dog "class inherits from the "Animal" abstract class - not the other way round.
The association arrows are almost always pointed at the containing object. I cover that later in this series because as you pointed out I should have done it that way. A Composition Association (Filled Diamond) is one in which if the container is destroyed so is the contained object. Aggregations (Empty Diamond) is one in which if the container is destroyed the contained lives on. Composition - "Part of" Aggregation - "Owns a"
This tutorial covers the UML 2.0 specification exactly. I do however know what you are referring to. Also, most people don't use the exact spec all of the time in the real world. As you'll see when you get to sequence diagrams I don't either :)
Thank you very much for the compliment :) I think because I aim to satisfy people that enjoy fast videos that I stand apart from many of the other tutorial people. I'm very happy that you enjoy them. Yes, I have over 500 videos on my TH-cam channel. Some of the old ones are terrible, but I do my best to always improve.
I check all my TH-cam personal messages. The ATM system I designed isn't much different from what you want to design. Instead of passing emails it passes an ATM transaction. Replace PIN number and valid card number with userid and password. They are almost exactly the same
If only everyone had a teacher like you. If only. Thanks to the TH-cam creators for giving people like you an opportunity to teach countless people like me who haven't had a good teacher, and most importantly, thank you!
Thank you for these. I am finding myself thrown into a OOA&D class with no real previous knowledge and you are thorough and do not skip "obvious" stuff like other videos do. Obvious comes with experience and these are perfect for me as a beginnger.
My undergrad is Computer Science and I have studied UML 8 years ago. As a PhD student I couldn't find a better refreshing tutorial than yours. good job. can you please post your slides so we can take notes on it. That would be great keep it up
Thanks for taking time to put these lessons together. It sure is nice hearing a coherent and native English-speaking instructor, as opposed to an unintelligible thick Indian accent.
Basically you need to create a use case description that goes over everything in exact detail. Then break everything into objects. Students, admins, email, everything becomes an object if it is an object in the real world. Then translate the use case description into a sequence diagram. You have the objects and the interactions, so you just have to connect them. My object oriented design tutorial shows you everything step by step. Tell me if you have questions after watching the 1st 2
I have seen that presented in both ways. In the real world unlike in books there are very few iron class rules. I for example always preferred to ignore most all diagrams except for sequence diagrams which I made very detailed. I never had a boss tell me what I was doing was wrong. As an architect at the time, all of the programmers under me loved working with me.
That is really up to you and your team. In the real world i normally always used simple class diagrams and verbose sequence diagrams and never had any trouble. Normally new programmers either create overly complex UML diagrams or don't understand them at all. You will normally be at the mercy of the systems architect were you are hired. i hope that helps :)
All architects work differently. I personally use sequence diagrams that are heavily commented. I also write very detailed usage descriptions. I make class diagrams, but I don't dwell on them. In the real world I do all of this stuff with paper and pencil. In groups I always work on a whiteboard
With both an Aggregation and a Composition, a class (I'll call it Dog) contains another class object (One is Bark and the other is FavoriteFood). With an Aggregation, since FavoriteFood could be used by other potential Animal objects (Non Dog Objects) then if the Dog object is destroyed FavoriteFood could continue to exist. With a Composition, Bark couldn't exist or would have no meaning without the Dog object (Assuming that no other Animals bark) Does that help?
The best explanation ever.. Your articulation of voice is amazing and gives more meaning to your words. Only few people know to talk like this, especially on dry subjects like requirement engineering, process modeling, diagrams etc.
You are correct. I'm sorry if I didn't make that clear. I think I got a bit tongue tied and I went back and revisited association arrows to correct any misunderstanding in the next few tutorials. Thanks for pointing that out :)
Hello Derek I am taking course On object oriented design from Alberta university (from Canada ) and there is some points are different 1- association is just when object is a parameter to method in other object class and in uml is just line (not doted line as in video) 2- aggregation is different a way from composition in code that aggregation is when u have something like array of the object of other class (and this array may have objects or may null) but in composition the object u use from other class need to be used every time u use this object (that can happen when u declare that object in yr constructor )
I just want to thank you for this tutorial service you provide. Currently taking an online community college course with no lectures provided and a very bland textbook; this is helping me immensely!
1.)@ 2:10: semantical error: encapsulation is not information hiding. encapsulation is the concept of encapsulating attributes and methods, which are logically dependent, i.e. the methods operate on the attributes. www.javaworld.com/article/2075271/core- java/encapsulation-is-not-information-hiding.html 2.)protected elements are also accessible to classes in the same package
Thank you :) I do my best to make everything understandable. I have one more video on the syntax of UML and then I'll get into using them in real world applications
I have no words to describe how you change my life with your videos! Thank you for all your tutorials..I'm not English-Speaker but your explanations are so clear that i understand quickly!
The system is all the objects combined. Break everything down into their smallest parts. If it is an object in the real world then make it an object in your use case. Watch my examples and you'll get it. I provide both fast and slow examples
I remember going through your java tutorials over 10-15 years ago as a teen... now I'm a plumber who makes video games at a high level in their spare time lol
I'm sorry, but I just started Android tutorials. I'm having a hard time finding the time to get those out quickly. I promise to cover Obj C as soon as possible. May God bless you as well :)
You put me in a total stupor with your Dog and Breen diagram. Composition relationship is drawn with a solid diamond. Just put an annotation at that point and yup, hammered down, everything will be fine. Other than that, good job!
Diagram at 14:30 says that Animal extends Dog I believe that you wanted to put it diffeently. And some slide before you put abstract class Animal below Dog. It was correct notation, but I believe it's more readable if abstracts are above inherited classes
It will be so kind of you if you initiate it not too late. As I am into objective c now a days just a beginner. Right now following lectures from stanford university on youtube but I am sure I will understand much more if you will deliver your lectures. May the CREATOR of all mankind bless your service.
Don't know if anybody said this already but I think you've got the arrow pointing the other way around on 14:02 Really enjoying your tutorials, btw. Planning on making my own once I feel prepared enough.
14:06 The arrow is facing the wrong way :) With interfaces, the arrow is from Animal to Dog (which is wrong), whilst it with Inheritance at 11:23 the arrow is from Dog to Animal (which is right). (Took me 30 mins to figure out, but hey...)
Thank you very much for the nice message :) Ill cover obj c and iDevice programming after I cover android. I'll cover it with the same detail I did with java
I'm sure u get this alot from people, but you are just simply the best. Do you have videos on other languages too.? just incase i might need them in future. Thanks again. your videos are great .:-)
I've used this kind of diagrams on C# before, still haven't used any on Java, but I would guess they are similar. My questions is: are class diagrams the only build in (or added with plugin) kind of UML diagrams in the popular programming languages like Java, C# etc. And where are the other type of diagrams (like the others in this playlist) usually used? I would guess software architects and "plan makers" in non-IT jobs as well. And also one can do it for himself, with a paper and pencil
What do you do if there is both a dependency and an association between two classes? Show both dependency and an association? or just the association since that is the 'stronger' one?
Derek, on the 'Abstract Class Diagrams' slide, at 14:20, If I am not wrong, the arrow between Animal and Dog classes seems to be pointing in the opposite direction. Please make a correction.
I made a little error there. Sorry about that. Yes you should definitely make videos. There are a ton of requests I get that I just don't have time to cover.
I'm sure someone has said this, but the inheritance arrow on abstract classes is backwards from when you introduced them. Also, why no cheat sheet for this one? I'm printing them all out for my cube but was sad not to find one for class diagrams... Excellent tutorials by the way. Excellent.
fantastic classes. man you are gifted to teach. congrats. one advice, put the number of lecture in the title. I`m just going back and forth to see which one is the next lecture. other than that.. man I wish I had you as my teacher.
You are just awesome to listen to and learn from. You have a good skill and thank you sir for sharing your knowledge. Kudos to you! Final exam tomorrow *fingers not even crossed, just ready*
You actually have aggregation and composition mis-matched. From what I was thought composition has a solid diamond while aggregation doesn't this is a very strange example because it's using both. If you're trying to demonstrate both I think in theory it breaks the composition definition. And the composition is more opinionated. But if the whole dog is destroyed the part breed isn't... What are you getting at here? Kind of bad confusing example. Ambiguity error please use the scope resolution operator :: lol
What are you getting at here? In composition the life cycle of the part class is dependant on the whole class. He is right about the diamonds as well. The part breed is destroyed if it is composition but not if it is aggregation. I like not this comment.
Your video has cleared much of the concepts I was fearing of. However I anticipate that would be a great service from you and help if you upload objective c programming tutorials. I love your voice pitch and clarity you use to simplify things. If possible plz bring your lectures in detail about OBJECTIVE C programming step by step.
I notice that around 14:43 you mentioned that dog is a subclass of animal and having an arrow head pointing at Dog class. Now when you mentioned at 11:29 that a subclass name Dog is created from the animal superclass and having the arrowhead pointing to the Animal superclass. Other than that I will give a like. Cool stuff !!
Love the video it is helping me complete an assignment as we speak. Do you have a video that uses a class diagram and goes to the code that would really be helpful!!!
Shouldn't the visibility modes of the methods in the 'Animal' class in ABSTRACT CLASS DIAGRAMS be declared protected (#) or public (+) for the subclass 'Dog' to inherit them?
Thank you very much.. During watching the video I had a feeling like if there was a simple example with c++ or other programming languages it would be much clearer.
Thank you Derek for another great tutorial. But i don't get when to use an association. For example in java, i have class dependency between A and B when class A has a method with type B as argument in one method. Composition is used when one class has an attribute which is of type of another class, thats clear as well. But when do i figure out if i have an association if i look at some java code? Best regards
Hello Derek, this is one good example of abstraction. 1) using java class codereview.stackexchange.com/questions/83387/building-data-abstraction-for-line-segments-using-type-abstraction 2) using python function objects codereview.stackexchange.com/questions/83626/building-data-abstraction-and-adt-for-rectangle-using-objects
![[UNCUT] The Loyal Pin ปิ่นภักดิ์ EP.15 (1/4)](http://i.ytimg.com/vi/TLBjiHvkKtE/mqdefault.jpg)
Guys, for aggregation and composition think of it this way
Aggregation(empty rectangle): If a dog breed goes extinct, dogs don't go extinct.
Composition(filled rectangle): If dogs go extinct, the dog breed also goes extinct.
+Dedokire *Very nicely put!*
*Thanks!!*
Reworded in a more lengthy fashion:
Aggregation: The 'Dog' contains a multitude (aggregation) of 'Breeds'; therefore, if a 'Breed' disappears, the 'Dog' remains.
Composition: Each 'Breed' is made up of (composed of) 'Dog'; therefore, if 'Dogs' disappear, 'Breeds' can no longer exist.
sorry to be so off topic but does anyone know a trick to log back into an Instagram account..?
I somehow lost the account password. I appreciate any assistance you can offer me!
@Israel Bryce Instablaster :)
Since Dog is a (sub-)class implementing and inheriting methods from the abstract Animal class, the arrow should be on the other side (see video at 14:05)
yea! i noticed too!
This is must be reverse.
@@utmostcreator Yup, he needs to fix that.
You're very welcome :) An Association occurs when a class contains a reference to another class "Has a". An Aggregation and a Composition are both Associations, but are more complex Associations. An Aggregation occurs when a class contains another class and the contained class can exist without the container class. A Composition ("Part of") also has a class that contains another. The only difference is that the contained can't exist without the container. I hope that helps
From your explanation of Aggregation & Composition, I think you got the notations wrong. Composition should be the filled diamond while Aggregation is the empty diamond. But you used them in the reverse.
okeyxyz Sorry about that error. You are correct.
+Derek Banas
you should create an annotation to let people know about that mistake. Luckily I saw this comment, but others might not see it. Anyways thanks a lot for this video.
+Derek Banas You made one more error. The arrow should be pointing on to the abstract class Animal and not the subclass as it is presented in the video. The "Dog "class inherits from the "Animal" abstract class - not the other way round.
Yeah same here jeez
Yeah you're right with your point
thanks derek, i remember watching these at uni, but i come back again every couple years to watch when i need to use uml at work
Thank you very much :) I'm extremely happy to be able to help people all over the world. Your nice comment is very much appreciated!
Learnt more in five minutes from you than a 3 hour lecture at college :-)
+Geordi La Forge Thank you for the compliment :) I'm glad I could help.
+Geordi La Forge video is 16 mins dammit watch till end
well he must have learned 9 hours worth then xD
The association arrows are almost always pointed at the containing object. I cover that later in this series because as you pointed out I should have done it that way. A Composition Association (Filled Diamond) is one in which if the container is destroyed so is the contained object. Aggregations (Empty Diamond) is one in which if the container is destroyed the contained lives on. Composition - "Part of" Aggregation - "Owns a"
This tutorial covers the UML 2.0 specification exactly. I do however know what you are referring to. Also, most people don't use the exact spec all of the time in the real world. As you'll see when you get to sequence diagrams I don't either :)
Thank you very much for the compliment :) I think because I aim to satisfy people that enjoy fast videos that I stand apart from many of the other tutorial people. I'm very happy that you enjoy them. Yes, I have over 500 videos on my TH-cam channel. Some of the old ones are terrible, but I do my best to always improve.
I check all my TH-cam personal messages. The ATM system I designed isn't much different from what you want to design. Instead of passing emails it passes an ATM transaction. Replace PIN number and valid card number with userid and password. They are almost exactly the same
You could do voice acting. You have a great voice for this type of thing.
+shootingblueyes Thank you for the nice compliment :)
If only everyone had a teacher like you. If only.
Thanks to the TH-cam creators for giving people like you an opportunity to teach countless people like me who haven't had a good teacher, and most importantly, thank you!
Thank you for the nice compliment :) I'm very happy to be of help.
Thank you for these. I am finding myself thrown into a OOA&D class with no real previous knowledge and you are thorough and do not skip "obvious" stuff like other videos do. Obvious comes with experience and these are perfect for me as a beginnger.
Thank you :) Happy I could help
My undergrad is Computer Science and I have studied UML 8 years ago. As a PhD student I couldn't find a better refreshing tutorial than yours. good job.
can you please post your slides so we can take notes on it. That would be great
keep it up
Thanks for taking time to put these lessons together. It sure is nice hearing a coherent and native English-speaking instructor, as opposed to an unintelligible thick Indian accent.
Basically you need to create a use case description that goes over everything in exact detail. Then break everything into objects. Students, admins, email, everything becomes an object if it is an object in the real world. Then translate the use case description into a sequence diagram. You have the objects and the interactions, so you just have to connect them. My object oriented design tutorial shows you everything step by step. Tell me if you have questions after watching the 1st 2
This greatly increases my understanding of UML. It brings to life the definitions I see in books.
Thank you :) I'm very happy it helped
I have seen that presented in both ways. In the real world unlike in books there are very few iron class rules. I for example always preferred to ignore most all diagrams except for sequence diagrams which I made very detailed. I never had a boss tell me what I was doing was wrong. As an architect at the time, all of the programmers under me loved working with me.
That is really up to you and your team. In the real world i normally always used simple class diagrams and verbose sequence diagrams and never had any trouble. Normally new programmers either create overly complex UML diagrams or don't understand them at all. You will normally be at the mercy of the systems architect were you are hired. i hope that helps :)
All architects work differently. I personally use sequence diagrams that are heavily commented. I also write very detailed usage descriptions. I make class diagrams, but I don't dwell on them. In the real world I do all of this stuff with paper and pencil. In groups I always work on a whiteboard
With both an Aggregation and a Composition, a class (I'll call it Dog) contains another class object (One is Bark and the other is FavoriteFood).
With an Aggregation, since FavoriteFood could be used by other potential Animal objects (Non Dog Objects) then if the Dog object is destroyed FavoriteFood could continue to exist.
With a Composition, Bark couldn't exist or would have no meaning without the Dog object (Assuming that no other Animals bark) Does that help?
thank you :) I didn't know if anyone would like these tutorials, but it is hard to teach oo design and refactoring without uml
Thank you :) Yes I get tongue tied every once in a while because non of this stuff is scripted. Sorry about that
I'm glad you found it useful. You're very welcome :)
The best explanation ever.. Your articulation of voice is amazing and gives more meaning to your words.
Only few people know to talk like this, especially on dry subjects like requirement engineering, process modeling, diagrams etc.
Thank you for the nice compliment :)
Thank you :) I do my best to put as much information into each video as possible.
You are correct. I'm sorry if I didn't make that clear. I think I got a bit tongue tied and I went back and revisited association arrows to correct any misunderstanding in the next few tutorials. Thanks for pointing that out :)
Hello Derek
I am taking course On object oriented design from Alberta university (from Canada ) and there is some points are different
1- association is just when object is a parameter to method in other object class and in uml is just line (not doted line as in video)
2- aggregation is different a way from composition in code that aggregation is when u have something like array of the object of other class (and this array may have objects or may null) but in composition the object u use from other class need to be used every time u use this object (that can happen when u declare that object in yr constructor )
Thanks for the input. Yes I messed up the dotted line by accident
@@derekbanas I appreciate so much your reply after 7 years from creating your video
I learnt a lot from yr channel
thanks a lot
Thank you :) I love talking with everyone
Thank you :) - is private, # is protected, + is public
I just want to thank you for this tutorial service you provide. Currently taking an online community college course with no lectures provided and a very bland textbook; this is helping me immensely!
That's great :) I'm happy that I could help
1.)@ 2:10: semantical error: encapsulation is not information hiding. encapsulation is the concept of encapsulating attributes and methods, which are logically dependent, i.e. the methods operate on the attributes.
www.javaworld.com/article/2075271/core-
java/encapsulation-is-not-information-hiding.html
2.)protected elements are also accessible to classes in the same package
On occasion I make typos. I'm glad you liked the video regardless :)
Thank you :) I do my best to make everything understandable. I have one more video on the syntax of UML and then I'll get into using them in real world applications
11:40 points from Dog to Animal (Dog -> Animal), meanwhile 14:20 points from Animal to Dog (Animal -> Dog). This is misguiding.
In the latter the arrow should also point towards animal: Dog -> Animal.
I have no words to describe how you change my life with your videos!
Thank you for all your tutorials..I'm not English-Speaker but your explanations are so clear that i understand quickly!
The system is all the objects combined. Break everything down into their smallest parts. If it is an object in the real world then make it an object in your use case. Watch my examples and you'll get it. I provide both fast and slow examples
I remember going through your java tutorials over 10-15 years ago as a teen... now I'm a plumber who makes video games at a high level in their spare time lol
I'm sorry, but I just started Android tutorials. I'm having a hard time finding the time to get those out quickly. I promise to cover Obj C as soon as possible. May God bless you as well :)
Sorry about that error. I have all the Umlet files available for download on this page newthinktank. com/videos/uml-video-tutorial/
Taught me more in this video than the lecturer taught me in 1 year
Turkish Gamer I'm glad I could help :)
Great video, literally got me going for a project at work, but your soothing voice almost put me asleep here at work too!
Thank you :) Sorry for making you tired
You put me in a total stupor with your Dog and Breen diagram. Composition relationship is drawn with a solid diamond. Just put an annotation at that point and yup, hammered down, everything will be fine. Other than that, good job!
Diagram at 14:30 says that Animal extends Dog
I believe that you wanted to put it diffeently.
And some slide before you put abstract class Animal below Dog.
It was correct notation, but I believe it's more readable if abstracts are above inherited classes
It will be so kind of you if you initiate it not too late. As I am into objective c now a days just a beginner. Right now following lectures from stanford university on youtube but I am sure I will understand much more if you will deliver your lectures. May the CREATOR of all mankind bless your service.
Thank you :) I edit the videos with iMovie
I seem to understand more from your video than my 4 hour-lecture class on Java.
+Randy Mam I'm happy that I could help :)
You're very welcome :) Thank you for taking the time to tell me the videos have helped
Don't know if anybody said this already but I think you've got the arrow pointing the other way around on 14:02
Really enjoying your tutorials, btw. Planning on making my own once I feel prepared enough.
The composite arrow should be filled and the one with aggregation should be left unfilled. Good clip tough!!!
You're a better teacher than my Object Oriented Development lecturer in uni. Thanks a million!
Thank you :) Im using UmLet
Thank you :) You are correct it is omitting it normally means that it doesn't matter
14:06 The arrow is facing the wrong way :)
With interfaces, the arrow is from Animal to Dog (which is wrong), whilst it with Inheritance at 11:23 the arrow is from Dog to Animal (which is right).
(Took me 30 mins to figure out, but hey...)
Iam brazilian and I've been enjoying all of your tutorials. I hope I learn how to programm as soon
Silvio da silva Thank you :) Hello Brazil!
at 14:00 the generalisation (inheritance) arrow goes in the wrong direction.
Peter Kelley Sorry about that error
I'll have to take a look. Thanks for pointing that out
Thank you very much for the nice message :) Ill cover obj c and iDevice programming after I cover android. I'll cover it with the same detail I did with java
never studied this lesson before and my exams are in 2- days...already watched 3 videos and from full stress mode I went to zero stress mode
That's great :) Best of luck on your exam
thank you mate!! :)
howd it go?
At 14:53 the arrow between abstract class and inheritance class points to the wrong direction or am I wrong?
No you are right, it seems like it's the opposite ( it's wrong )
I'm sure u get this alot from people, but you are just simply the best. Do you have videos on other languages too.? just incase i might need them in future. Thanks again. your videos are great .:-)
I've used this kind of diagrams on C# before, still haven't used any on Java, but I would guess they are similar.
My questions is: are class diagrams the only build in (or added with plugin) kind of UML diagrams in the popular programming languages like Java, C# etc.
And where are the other type of diagrams (like the others in this playlist) usually used?
I would guess software architects and "plan makers" in non-IT jobs as well. And also one can do it for himself, with a paper and pencil
You're very welcome :)
Sorry I made a little error.
Thank you :) It is very nice of you to say that
You're welcome :)
What do you do if there is both a dependency and an association between two classes? Show both dependency and an association? or just the association since that is the 'stronger' one?
Hi Derek, I just wanted to thank you! I have really been struggling with some of the concepts of OOAD and your videos are really helping. Thanks
Derek, on the 'Abstract Class Diagrams' slide, at 14:20, If I am not wrong, the arrow between Animal and Dog classes seems to be pointing in the opposite direction. Please make a correction.
I made a little error there. Sorry about that. Yes you should definitely make videos. There are a ton of requests I get that I just don't have time to cover.
The presentation software I use is called keynote
Derek... you absolute legend... I salute you sir!
I'm sure someone has said this, but the inheritance arrow on abstract classes is backwards from when you introduced them.
Also, why no cheat sheet for this one? I'm printing them all out for my cube but was sad not to find one for class diagrams...
Excellent tutorials by the way. Excellent.
fantastic classes. man you are gifted to teach. congrats. one advice, put the number of lecture in the title. I`m just going back and forth to see which one is the next lecture. other than that.. man I wish I had you as my teacher.
Thank you for the nice compliment :) I'll see what I can do about the titles
Hi Derek,
It seems a typo.
The arrow should point from class Dog to abstract class Animal. Also it should be a dashed arrow.
Best regards and thanks.
You are just awesome to listen to and learn from. You have a good skill and thank you sir for sharing your knowledge. Kudos to you! Final exam tomorrow *fingers not even crossed, just ready*
+777Jimihendrix Thank you for the compliment :) Best of luck on your exam!
Спасибо. Я делаю лучшее, что я могу. Я рад, что вам нравится видео.
You actually have aggregation and composition mis-matched. From what I was thought composition has a solid diamond while aggregation doesn't this is a very strange example because it's using both. If you're trying to demonstrate both I think in theory it breaks the composition definition. And the composition is more opinionated. But if the whole dog is destroyed the part breed isn't... What are you getting at here? Kind of bad confusing example. Ambiguity error please use the scope resolution operator :: lol
What are you getting at here? In composition the life cycle of the part class is dependant on the whole class. He is right about the diamonds as well. The part breed is destroyed if it is composition but not if it is aggregation. I like not this comment.
Actually, you're wrong and Kristopher is right.
Abstract methods in Abstract classes cannot be private (in C#) . The eg: shown @ 14 : 48 for animal (eat and noise is shown as private.
Aggregation:
Bee--------Swarm
A Bee CAN exist without a Swarm
Composition:
Swarm-----------◀▶ Bee
A Swarm CAN'T exist without any Bee
Your video has cleared much of the concepts I was fearing of. However I anticipate that would be a great service from you and help if you upload objective c programming tutorials. I love your voice pitch and clarity you use to simplify things. If possible plz bring your lectures in detail about OBJECTIVE C programming step by step.
I notice that around 14:43 you mentioned that dog is a subclass of animal and having an arrow head pointing at Dog class. Now when you mentioned at 11:29 that a subclass name Dog is created from the animal superclass and having the arrowhead pointing to the Animal superclass. Other than that I will give a like. Cool stuff !!
Joe Swanson is on duty to serve :)
THANK YOU SO MUCH FOR MAKING ME PASS MY EXAMS SIR. C++, C, java, diagram, i love you so much. keep up with the good work! :D
great video! i pretty much took all the notes and took me more than 1 hrs to go through them :)
Love the video it is helping me complete an assignment as we speak. Do you have a video that uses a class diagram and goes to the code that would really be helpful!!!
Zachary Harris Thank you :) Check out my object oriented design tutorial for that th-cam.com/video/fJW65Wo7IHI/w-d-xo.html
you say in the video that composition is the open diamond and aggregation is the filled in diamond, and I have been taught the other way around..?
Thank you very much :) Ill see if I can post the whole file so you can open it and output in any format tomorrow
You sir, are the real MVP...
+Mo Gaucho Thank you :) I appreciate that
thanks for the intro Andy from the Office
That's funny 😁
Very good tuts, thanks you very very much. Btw, what tool you used when transit from nor slide to another? It looks very cool way
Really handy video for getting my head around these concepts, thanks!
Shouldn't the visibility modes of the methods in the 'Animal' class in ABSTRACT CLASS DIAGRAMS be declared protected (#) or public (+) for the subclass 'Dog' to inherit them?
Sorry, but I don't have them
Thank you very much.. During watching the video I had a feeling like if there was a simple example with c++ or other programming languages it would be much clearer.
I'm glad I could help :) Maybe I can do that in my future C++ tutorial
Thanks to you.. :) The effort you have given is well spend for sure.. :D
I think we have quickly gone thru object diagrams and OCL, Are we going to discuss these two topics with proper examples in OOD lecture series?
Ethashamuddin Mohammed Yes I cover that in my object oriented design tutorial and then again in refactoring
Derek Banas Hope we take real world applications to discuss more on these diagrams in OOD and refactoring series
Great video man! I'm a CS major and you've really helped me grasp these concepts!
+Jamie Jackson Thank you :) I'm glad I could help
Thank you very much :) I do my best
Thank you Derek for another great tutorial. But i don't get when to use an association. For example in java, i have class dependency between A and B when class A has a method with type B as argument in one method. Composition is used when one class has an attribute which is of type of another class, thats clear as well. But when do i figure out if i have an association if i look at some java code?
Best regards
Hello Derek, this is one good example of abstraction. 1) using java class codereview.stackexchange.com/questions/83387/building-data-abstraction-for-line-segments-using-type-abstraction
2) using python function objects
codereview.stackexchange.com/questions/83626/building-data-abstraction-and-adt-for-rectangle-using-objects